This invention relates to an improved shifting mechanism for coupling a driving mechanism to a driven mechanism and more particularly to such a shifting mechanism that is particularly adaptable for utilization in the shifting arrangement of an outboard engine or propelling unit of an inboard/outboard drive.
Many types of shifting mechanisms employ dog or positive clutches for coupling a driving member to a driven member. A typical example of such an application is in the transmission mechanism of an outboard engine or inboard/outboard drive. In conjunction with such arrangements, there are a pair of gears rotatably supported on the output shaft and which rotate in opposite directions. A shifting mechanism including a sliding sleeve having positive clutching elements is mounted between these gears and is shiftable into engagement with corresponding clutching mechanism on the gears for coupling the sleeve to the output shaft which drives the propeller. With such an arrangement, of course, it is important that the sleeve be brought quickly and positively into engagement with the respective gear so as to avoid the chattering which occurs if the engagement is not rapid and accurate. In addition to the noise, such chattering of course will cause wear in the system. In order to avoid these problems, it has been proposed to provide some form of positive assist such as a fluid motor to affect the shifting mechanism. Alternatively, it has been proposed to employ a spring arrangement which will provide a constant force for urging the clutch element into engagement. Both arrangements are, obviously, expensive and significantly complicate the shifting mechanism.
It is, therefore, a principal object of this invention to provide an improved and simplified shifting mechanism.
It is another object of this invention to provide an improved shifting mechanism wherein positive clutch elements are brought into engagement with a uniform force.
It is yet a further object of this invention to provide an improved and simplified shifting mechanism for an outboard drive unit.